Thermostatically controlled circuit controller



July 18, 1933. o, oss 1,918,491

THERMOSTATICALLY CONTROLLED CIRCUIT CONTROLLER Filed Dec. 2, 1930 A TTORNEYS.

Patented July is, 1933 UNITED STATES PATENT OFFICE OSCAR A. BOSS, 013 NEW YORK, N. Y., ASSIGNOR TO GENERAL PLATE COMPANY, 01 ATTLEBORO, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS THERMOSTATICALLY CONTROLLED CIRCUIT CONTROLLER Application filed December 2, 1980. Serial No. 499,427.

This invention refers to automatic'temperature controlled electric switches and more particularly to such devices as are employed in electric sadirons'or similar heat application devices.

One object of this invention is the provision of. a quick-acting, temperature controlled electric switch wherein the normal contact pressure is maintained at substantially maximum until the contacts are actually separated for opening the circuit controlled thereby.

Another object is the provision of a quickacting, temperature controlled electric switch wherein one of two thermally afiected contact actuating elements, when moving rapidly, is brought to an abrupt stop without limiting the movement of the other element, whereby a quick separation of contacts is affected during a state of maximum contact pressure between the contacts.

Another object is the provision of an automatic temperature controlled electric switch wherein two thermally affected contact actuating elements having differing tempera-' ture response characteristics are included,

for more effectively obtaining a quick separation of the contacts during Joint movement of such elements.

Another object is the provision of a quick acting thermostatically controlled electric switch wherein a single insulated juncture acts to insulate a plurality of independent co-operating movable circuit closers.

Another object is the provision of a quickacting thermostatically controlled electric switch wherein all the contacts subject to impact are rigidly supported as by a metalto-Inetal joint, thereby minimizing lo0sening of the contacts due to the hammering of the contacts when in operation.

Otherobjects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of various possible embodiments of the invention,

Fig. 1 is an axial section of a switch embodying the present invention;

Fig. 2 is a side elevation of the switch illustrated in Fig. 1, but showing certain thermostatic elements in their alternative position; and,

Fig. 3 is a top plan view of the switch shown in Figs. 1 and 2. Lines II and IIII on Fig. 3 illustrate the positions of Figs. 1 and 2, respectively, with relation to Fig. 3.

' Similar reference characters indicate corresponding parts throughout the several views of the drawing.-

Referring now more particularly to the drawlng, numeral 1 indicates a base member, which has a plurality of peripheral dependng arms or stop portions 2, which are each in turn provided with stop faces or abutments 3 substantially parallel to the plane of the base member 1. Rigidly secured to the central, under surface of base member 1 is a collar member 10. The member 10 has a firmly clamps the central portion of a thermostatlc disc 6. The thermostatic disc 6 preferably comprises a concave-convex bimetallic member of the type disclosed in Spencer Patent 1,448,240, and which is conv peripheral groove 9 therein, which groove 9 The disc 6 extendsradially from its cen- V tral mounting to a region where its movement is limited by the engagement of its peripheral portion 5 with the abutments 3 of the base member 1. That is, the diameter of the disc 6 is such that it is enclosed within the base member and its depending arnis.

Spacedly mounted on the under surface of the disc 6 are a plurality of contacts or circuit controlling members 7.

An insulating sleeve 12 fits within the collar 10, and a central terminal post 11 in turn fits within the sleeve 12. The post 1 is in the form of a bolt, having a head 16 at its lower end. Supported between the head 16 and a washer 17 at its central region 19 is a second thermostatic disc 15, similar to 5 the disc 6 except in the particulars hereinafter set forth. A nut 18 serves to hold the post' 11 and disc 15 in the desired relationship. Insulating washers 13, together with the insulating sleeve 12, completely, electri- 10 cally isolate the post 11 and disc 15 from the base 1 and disc 6. Additional nuts are provided on the upper end of the post 11 for effecting external electrical connections.

The disc 15 is of a smaller diameter than the disc 6, so that it may snap back and forth without engaging the abutments 3. Contacts or circuit controlling members 20 are mounted on the upper surface of disc- 15 in position to engage the contacts 7 on disc 6. Discs of the type of 6 and 15 have certain definite operative characteristics. For instance, considering the discs 6 and 15 in their Fig. 1 position to be concavo-convex and cold, when the external temperature rises to a predetermined maximum (for each disc) their positions change to convexo-concave, as shown in Fig. 2. Such a temperature may be designated as T6 and T15 for the discs 6 and 15, respectively. Now, if the external heating is discontinued and the discs allowed to cool, at a second set of predetermined temperatures (for each disc) are reached, the discs return once more to their concavo-convex, or Fig. 1 position. These second temperatures may be represented by 256 and t15 for the discs 6 and 15, respectively. The interval between T6 156 is known as the operating temperature differential for the disc 6, and the interval between T15 and $15 is similarly the operating temperature diil'erential of the disc 15.

In the present invention the operating temperature differential of the disc 6 is desirably somewhat less than, and within the limits pf, the differential of disc 15; specifically, T6 18 preferably somewhat lower than T15, and t6 is preferably somewhat higher than t15, although in each instance the difference is rather slight.

Having thus described the construction of the invention, its operation, as set forth hereinafter, will now be understandable:

Normally, in cold position, the contacts 7 and 20 are engaged, the thermostatic member 15 being stressed to produce a substantial pressure between said contacts. At a predetermined rise in temperature of the members 6 and 15 the outer edge portion of member 6 slowly moves downwardly, thereby stressing the outer edge 21 of member 15 downwardly and tending to increase the pressure between contacts 7 and 20. As the rise in temperature continues the thermostatic member 15 also tends to move downwardly. However, the greater power of the member 6 causes contacts 7 nevertheless to engage contacts 20 firmly. Finally, at a further rise in temperature, the member 6 reaches its upper critical temperature and abruptly changesits sha etothatshown in Fig. 2. By so doing, the iso 6 also stresses member 15 downwardly. Almost immediately the upper critical temperature of disc 15 is reached and disc 15 also abruptly changes its form to that shown in Fig. 2. During the abrupt movement of both members the edge 15 of member 6 engages the abutments 3 and is restrained from final movement all the way to its hot, stable position. However, the

outer edge 21 of member 15 continues all the way to its lower hot, stable position, in this manner abruptly separating contacts 7 and 20 to prevent arcing therebetween as the circuit controlled thereby is opened.

Upon cooling, of the thermostatic members 6 and 15, the member 6, owing to its strained position, and to its higher lower critical temperature first moves to its cold position as shown in Fig. 1. Upon further cooling, the lower critical temperature of member 15 is reached, and member 15 abruptly changes its form to that shown in Fig. 1, thereby effecting engagement of contacts 7 and 20 again to close the circuit.

The thermal response of thermostatic members 6 and 15 is such that during the initial, cold-to-hot abrupt movement of said members, the member 6 has a greater tendency to move or change its shape, thereby maintaining substantially maximum contact pressure between contacts 7 and 20 until the movement of member 6 is abruptly stopped by the abutments 3.

Whereas the portion of thermostatic members 6 and 15 clamped between head 16 and collar 17, and the portion of member 6 clam d in groove 9, are shown as of bimeta lic structure, they may well be of thermostatic or non-monometallic structure. This is accomplished, preferably by removing one of the metals of the bimetallic structure and leaving, the other, or by removing one of the metals and replacing 'it with a metal similar to the remaining metal whereby the clamped portion is of the same thickness as the bi-metallic portion, albeit comprising but one metal.

Through the feature of the insulating sleeve 12 and washers 13 an advantageous mounting is effected, inasmuch as this permits the contacts 7 and 20 to beliveted or otherwise rigidly aflixed to the discs 6 and 15. In prior analogous switches. it was necessary to insulate the mounting of contacts on the discs, and this entailed a non-rigid mounting which was, in some cases, easily loosened and battered by the hammering of the contacts in their operation. The manner in which the discs 6 and 15 are electrically insulated permits the rigid mounting of the contacts on the discs and obviates the noted disadvantage of prior structures.

' While the invention has been described herein in connection with the use of thermostatic discs of the type shown by Spencer Patent 1,448,240, it will be apparent that other types of thermostatic systems, which have two positions of stability and pass from one to another of said positions abruptly, may likewise be used. a

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying outthe above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What I claim is 1. A quick-acting make and break switch comprising a supporting member, athermostatic element having a movable portion thereof capable of assuming one of two substantially stable extreme positions in response to predetermined thermal conditions, a second thermostatic element having a mo vable portion thereof also capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, means associated with the supporting member for supporting the elements in operative relation, the movableportion of one of the elements having a greater distance of travel than the similar portion of the other member.

2. A quick-acting make and break switch comprising a. supporting member, a thermostatic element having a movable portion thereof capable of assuming one of two subfiantially stable extreme positions in response to predetermined thermal conditions, a secondary thermostatic element having a movable portion thereof also capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, means associated with the supporting member for supportstatic element having amovable portionv thereof capable of assuming either oneof two s'ubstantialy stable extreme positions response to predetermined thermal cond tions, a second thermostatic element having a comprising a supporting member, a thermostatic element having a movable portion thereof capable of assuming either one of two substantially stable extreme positions in re sponse to predetermined thermal conditions, a second thermostatic element having a movable portion thereof also capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, means associated with the supporting member and including electrical insulating means, for supporting the members in operative relation, and means limiting the movement ofthe movable portion. of one of the members without limiting the movement of the movable portion of the other member.

5. A quick-acting make and break switch comprising a supporting member, a thermo static element having a movable portion thereof capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, a second thermostatic element having a movable portion thereof also capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, means associated with the supporting member and including electrical insulating means, for'supp'orting the thermostatic members in operative relation, and circuit controlling members supported by the movable portion of the elements, the circuit controlling members supported by one of the movable portions being arranged to operatively engage the circut controlling members supported by the movable portion of the other element.

6. A quicleacting make and break switch comprising a supporting member, a thermostatic element having a movable portion thereof capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, a. second thermostatic element having a movable portion thereof also capable of assuming either one of two substantially stable extreme positions in response to predetermined thermal conditions, means associated with the spacedly supporting the central portions of the discs to position the peripheries thereof in operative relation one to the other, and contacts on said elements, the contacts on the one element being arranged in contacting relation to the contacts on the other element.

8. quick acting thermostatic switch comprising, a stressed bimetallic thermostatic element having a rigidly supported portion and a movable portion, the movable portion being arranged to abruptly move from one substantially stable position to another substantially stable position in response to change in temperature, a contact supporting member having a rigidly supported portion and a movable portion, the movable portion having contacts supported thereby engaging a correlated contact supported by the thermostatic element when the movable portion thereof is positioned in one stable position, the movable portion of the contacting supporting member being constrained toward and arranged to move simultaneously with the movable portion of the thermostatic element during the movement thereof from one position to the other whereby the correlated contacts of both the movable portions are rapidly moved in engagement during the movement of the movable portions, and one or more arresting members positioned in the path of the movable portion of the contact supporting member for abruptly arresting the movement thereof from one position to 'the other, the movement being abruptly arrested after the movable portions have attained a comparatively high rate of travel in moving from one position to the other and before the completion of the movement of the movable portion of the thermostatic element.

9. A quick acting thermostatic switch comprising, a thermostatic member arranged to move abruptly from one substantially stable position to another substantially stable position at high'velocity in response to change in temperature. a plurality of primary contacts moved thereby, the contacts being arranged to be moved from one contacting position to another contacting position at high velocitv as the thermostatic member is moved at high velocity from one substantially stable position to the other substantially stable position, a movable member arranged to be moved from one contacting position to another contacting position as the thermostatic member is moved from stable position to the other stable position, a plurality of secondary contacts moved thereby arranged to engage the primary contacts, the movable member being arranged to move the secondary contacts in engagement with the primary contacts at substantial pressure therebetween during the movement of the members from one position to the other, and means for abruptly arresting the movement of the movable member without arresting the movement of the thermostatic member during the period the members are moving at high velocity and before the thermostatic member has completed the movement thereof.

10. A switch comprising a base, a selfactuating thermostatic device mounted on said base, said thermostatic device having two positions of relative stability determined by ambient temperature conditions, and a region which moves abruptly between said positions of stability, at least one contact member mounted on said region, and an element carrying a second contact member adapted to cooperate with said first-named contact member to control a circuit, said element being constructed and arranged to move with said mobile region through a portion of its travel between said positions of stability.

11. A switch comprising a base, a selfactuating thermostatic device mounted on said base, said thermostatic device having two positions of relative stability determined by ambient temperature'conditions, and a region which moves abruptly between said positions of stability, at least one contact member mounted on said region, an element carrying a second contact member adapted to cooperatev with said first-named contact member to control a circuit, said element being constructed and arranged to move with said, mobile region through its travel, and means associated with said base restricting the motion of said element to a portion of the total travel of said mobile re on.

12. A switch comprising a use, a thermostatic disc mounted at its central region on said base, the periphery of said disc having two positions of relative stability determined by ambient temperature conditions, said periphery moving abruptly between said positions of stability, at least one contact mounted on the periphery of said disc, an element also mounted on said base and having a contact thereon adapted to cooperate with said first-named contact to control a circuit, said element being constructed and arranged to follow the periphery of said disc through its abrupt motion whereby said contacts are maintainedtogether, and at least one abutment for said element, said abutment positively preventing said element fromv following said periphery throughout its entire range of motion, and. thereby causing separation of said contacts when said element engages said abutment.

13. A switch comprising a base, a thermostatic disc mounted at its central region on said base, the periphery of said disc having two positions of relative stability determined by ambient temperature conditions, saidperiphery moving abruptly between said positions of stability, at least one contact mounted on the periphery of said disc, a second disc also mounted at its central region on said base, concentrically with said thermostatic disc, the peripheral region of said second disc being free for motion, at least one contact on the peripheral region of said second disc adapted to cooperate with said first-named contact to control a circuit, said second disc being constructed and arranged such that its peripheral region follows the periphery of said thermostatic discthrough its abrupt motion, whereby said contacts are maintained together, and atleast one abutment associated with said base, said abutment engaging the peripheral region of said second disc positively to prevent such region from following the periphery of said thermostatic disc throughout its entire range of abrupt motion', and thereby causing abrupt separation r of said contacts.

14. A switch comprising a pair of spaced, concentrically mounted thermostatic discs each of which has two positions of relative stability, and cooperating contacts on the facing surfaces of saiddiscs, said discs being adapted to maintain said contacts pressed together under one predetermined temperaturecondition, but to separate said contacts upon the achieving of a second predetermined temperature condition.

- 15. A switch comprising a pair of spaced, concentrically mounted thermostatic discs each of which has two positions of relative stability, and cooperating contacts on the facing surfaces of said discs, said discs being adapted to maintain said contacts pressed together when both said discs are in one of their positions of stability, but to separate said contacts when both said discs are in their respective second positions of stability.

16. A switch comprising a pair of spaced, concentrically mounted thermostatic discs each of which has two positions of relatively stability, and cooperating contacts on the facing surfaces of said discs, said discs being adapted to maintain said contacts pressed together when both said discs are in one of their positions of stability, but to separate said contacts when both said discs are in their respective second positions of stability, and insulating material electrically insu1ating said discs.

17. A switch comprising a pair of spaced, concentrically mounted thermostatic discs each of which has two positions of relative stability, and cooperating contacts on the facing surfaces of said discs, said discs being adapted to maintain said contacts pressed together when both said discs are in one of their positions of stability, but to separate said contacts when both said discs are in their respective second positions of stability, said discs having difierent operating temperature differentials.

18; A switch comprising a plurality of snapacting thermostatic elements, said elements carrying cooperating contacts, and said elements having different operating temperature diflerentials.

OSCAR A. ROSS. 

